Device for feeding strip metal to power presses having positive works clamp releasing means



July 12, 1960 A. F. GROLL 2,944,458

DEVICE FOR FEEDING STRIP METAL TO POWER PRESSES HAVING POSITIVE WORKS CLAMP RELEASING MEANS Filed Aug. 23, 1956 3 Sheets-Sheet 1 INVENTOR.

fi L l///V F GROLL ATTORNEY July 12,1960 A F GROLL DEVICE FOR FEEDING STEIP METAL T0 POWER PRES ES HAVING POSITIVE WORKS CLAMP RELEASING MEANS 5 Sheets-Sheet 2 Filed Aug. 23, 1956 "I'Illla Q INVENTOR.

F GROL L ATTO NEYS y 1960 A. F. GROLL DEVICE FOR FEEDING STRIP METAL T0 POWER PRESSES HAVING POSITIVE WORKS CLAMP REL Flled Aug 23, 1956 3 8 5 n 4 e h 4 S 4 s 9 m 2 e s v m E3 M G N I S A E INVENTOR. AL l //V F GROLL BY WZ M-M ATTORNEYS United seesilmwf DEVICE FOR FEEDING STRIP METAL Tl) POWER PRESSES HAVING POSITIVE WORKS CLAIHP RE- LEASING NIEANS Alvin F. Groll, 130x347, Napoleon, Ohio Filed Aug. 23,1956, Ser. No. 605,766

6 Claims. ((31. 83-437) Strip metal, usually steel, from which shapes are to be cut by power presses or other metal working apparatus is supplied in coils from which the strips are withdrawn step by step in synchronism with cutting presses through which the strips are fed.

Automatically controlled power presses and even those that are controlled manually or by foot pedalsare capable of cutting shapes from the strips withgreat rapidity. Be; cause of the high cost of power press installations and the high cost of operating them, it is important that provisions be made for feeding the strips to the presses as rapidly as the presses are capable of cutting shapes from them. It. is a important also that the strips be fed in increments'which movements of the "are uniform and which supply *exactly thedength of strip required for each cutting, no more no less, so that "waste of materialanrl imperfect shapes both are avoided.

It is .anobject of this invention to provide adeviceffor f somewhat when the feeding device is assembled with the feeding strip'metal stock to a power press'or other metal working apparatus with greater, rapidity than has heretofore been practicable. 1

It is a further object of the invention to provide a device which is capable of feeding strip metal to a power press in increments, the lengths of which can be adjusted to so conform to the length required for each cutting as to minimize waste. 7

It is a further object to provide a device which is capable of feeding strip metal to power presses in increments of such exact uniformity as to avoid spoilage of shapes being produced by the power press. I

It is a further object to provide astrip stock feeder having means to grip the strip stock between jaws which move forwardly together intermittently to advance the *Strip stock by increments. t o

It is a further object to-Qprovide a strip stock feeding device having jaws which 'r'no've with forward and back strokes, the jaws being clamped upon the strip stock during the forward stroke and'relea'sed to move freely along the strip stock during the. backstroke, the 'devic'ehaving abrake which intermittently grips 'thestrip stock t'o hold it stationary, the operation arm-e jaws and the operation of the brake being so coordinatedwith each other a nd with the operation of apower-pressthat the brake rele'asesfthe;

strip stock during the forward'movementfof'thejaivs' and grips the strip stock during the back movement' of the jaws when they slide freely along'th'e stock; '1'

Other objects and many advantages of the invention will appear upon perusal of the following descriptionjillu's- I trated by the accompanying drawings in which? 7 Fig. I is a front elevational view of a power press-having the strip stock feeding device of y inv ntiqn'ineerporated therewith; A Fig. II is a front elevational view on a' larger scale of the strip stock feeding device of my invention, some parts being broken away and most of the "other parts being shown in section; V, a

Fig-III is a plan view with parts in section taken along the-line III of Fig. II but showing the strip advancin mechanism at'the endear its back stroke;

' l aligned with' th'e extension before beinglsecured thereto.

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is driven by a shaft 2 which reciprocates a slide 3 to force. a die 4 into a mating'die, not shown, that is fixed in a die' block 5. The die block 5 in the type of press illustrated is supported by bolster 6 which usually is a permanent part of the frame of the press.

Fixed to the bolster 6 of the power press 1 is a cantilever 7 upon which is mounted the device of this invention for feeding strip metal to the press. The mechanism of the device is supported upon a base plate 11 which rests upon the cantilever 7 and after being properly positioned thereon is secured in place. The cantilever 7 has an oblong opening 8 into which downwardly projectingparts may extend without interferencef Erected upon the b Q e plate 11 and rigidly fixed thereto is a housing 14; in whichis journaled, by means of ball i bearings 15 and 16, a vertical shaft 17. A nutor collar :18 fixed upon the shaft 17 and engaging the housing 14 serves to take the downward thrust exerted by the shaft 17; The shaft 17 is dividedinto two parts connected by a sleeve 19 so that the length of the shaft may'be adjusted power'pre'ss. 1

the/gear 21 being fixed to the upper end of the shaft 17 While'the gear 22 is fixed to an extension 23 that is connected, by means of a coupling 24, to the crank shaft 2 of the power press so that the extension 23 turns with the crank shaft 2.

p In order to insure permanentperpendicularity between the axes of the shaft 17 and the extension 23, a spindle 25 coaxial with the extension 23 is journaled in an elongated bea ring "26 formed in the gear box. 20, while the shaft 17 is journaled in anelongated b0ss;27 on the gear box. The spindle 25 maybe integral with the extension 23 or it may be fabricated separately and centered. and

7 Antifricti'o'n bushings 28 andfZQ are interposed between "the shaft 17 and the boss 27 and betweenithe spindle 25 and the elongated mana es, and .lubricantretaining packing ringsorseals 30' and 3 l surround the shaft 17 and'ext'ension 23; f 7 a The upper surface the: plate 11. lies nearly. in the "same horizontal plane as the;upper surfacei'of thedie f metal from whichfshapesjare to be out is v threaded through the device for feeding" the strip "and through the power press so that the stripfslid'eslover the upper surface of thebase plate 'llfand theupper surface of the die block 5.

- To slide the stripdnte'rmit't'ently forwardf(i.e;, from. left to right as seen in -Figs. I and III of the drawings), a crank 32- is fixed upon the lower end'of the shaft 17. I'nI't he lower side of the crank32 isan undercut channel 33 within which ismounted for slidable adj ustrnent'a cross head 34 from 'which' a 'crank pin 35 projects downwardly. Positioning the crank pin 35 nearer to the axis of the vertical shaft 17 reduces the throw of the crank While positioning the crank 'pin farther from the axis of the vertical shaft increases the throw of the crank. The crank pin 35' is positioned by means'of an adjusting screw 36 which is turnably mounted in-the crank 32'and is: threaded into'the cross head'u. i

The crank pin 35 is surrounded by a composite collar and bushing 37 which serves to space the crank 32 fiom a connecting link 38 and also serves as a bushing through which the crank pin is pivoted to one end of the connecting link 38.

The other end of the connecting link 38 is pivoted by means of a wrist pin 39 to a horizontally reciprocatory carrier 4%) which is mounted between gibs 41 that lie upon the upper surface of the base plate 11. The base plate 11 has a large opening 42 over a part of which the reciprocatory carrier 4-0 extends and within which lies a bumper bar 43 that is secured to the reciprocatory carrier 40 and reciprocates therewith within the opening 42 of the base plate 11. The opening in the base plate 11 extends over part of the oblon opening 8 in the cantilever 7.

Bumper pins 44 and 45 project from opposite sides of the bumper bar 43, and located at the ends of the paths of movement of the bumper pins-44 and 45 are stop screws as and 47 which are threaded into cleats 48 and 49 that are fixed to the bottom of the base plate 11. By turning the stop screws 46 and 4-7 they may be adjusted to limit the travel of the bumper pins 44 and 45, the bumper bar $3 and the reciprocatory carrier 40 to slightly more than the reciprocal movement imparted by the crank 32 and connecting link 38. The bumper pins do not strike the stop screws when the device is functioning normally.

The reciprocatory carrier 40 and the bumper bar 43 have registering slots within which are mounted a lower jaw t and an upper jaw 51 adapted to be clamped upon a metal strip. The dimensions of the jaws are such that the jaws extend substantially across the entire width of the widest strip that the device is designed to handle. The iower jaw 50 is fixed within the slot of the bumper bar. The upper jaw 51 is pivoted on an axis perpendicular to the direction of reciprocation of the reciprocatory-carrier 40 and has a cam face 5 2 so shaped as to clamp the metal strip being handled more tightly when the strip is being pulled forward (i.e., to the right as seen in Figs. I and III of the drawings) and to exert less clamping eifect on the back stroke of the reciprocatory carrier 4%).

In order to positively eliminate the clamping effect from the strip during the back stroke, the cam face 52 of the jaw 51 is relieved as indicated at 53, and especially devised mechanism is employed to positively tilt the jaw 51 to bring the relieved portion 53 over the upper face of the strip. The especially devised mechanism includes a push bar 54 slidably fitting in a groove in the top of the reciprocatory carrier 40 and having one end engageable with the upper part of the pivoted jaw 51. The other end of the push bar 54 is engageable with a rib 55 fixed on the lower side of the connecting link 38. The push bar 54 is so located (see Figs. III, IV and V) that it is engaged by the rib 55 only during the back stroke of the reciprocatory carrier 40 and the engaging surfaces of the push bar and the rib are both curved about the axis. of the wrist pin 39 so that the push bar is held against the upper part of the pivoted'jaw 51 while the rib swings over the end of the push bar during the back stroke. In order to move the push bar 54 quickly at the beginning of the back stroke, rather steep 'cam surfaces 56 and 57 are formed at the corners of the push bar 54 and the rib 55 that come into engagement as the connecting rod moves over center when the reciprocatory carrier 40 is momentarily stationary at the end of its forward stroke. Thus the cam face 52 of the pivoted jaw 51 is moved away from the strip while the strip'and the reciprocatory carrier 40 both are standing still.

To insure against vagrant movements of the metal strip while it is not clamped between the jaws 50 and 51 that are carried by the reciprocatory carrier 40 the strip is gripped by a brake during the back stroke of the reciprocatory carrier. The brake is actuated by a cam 58 which is fixed upon the vertical shaft 17 and which acts by the brake.

upon a horizontally slidable member 59 terminating in a wedge 60 which underlines a roller 61 from which depends a brake element 62. The brake element 62 is constantly urged by gravity and by spring tension toward a stationary brake element 63, the brake element 62 being located above the strip and the brake element 63 being located below the strip. While the wedge 60 is forcibly held beneath the roller 61. by the action of the cam 58 on the horizontally slidable member 59 the brake element 62 is held out of gripping engagement with the strip. The high point of the cam 58 and the crank 32 extend radially from the axis of the vertical shaft 17 in the same direction so that the wedge 69 ispushed to its greatest extent under the roller 61 to release the brake just before the strip is clamped by the jaws 50 and 51 at the end of the back stroke of the reciprocatory carrier 40.

Whenever it is desired to release the brake, e.g. for the purpose of threading a strip of metalthrough the machine, the brake may be released by means of a handle 64 which turns an eccentric 65 to lift the brake element 62 against the forces of gravity and spring tension.

A pair of guide rollers 66 are adjustably fixed upon the base plate 11 being so spaced and positioned that a strip of metal passing between them will be guided into the housing 14, between the jaws 50 and 51 and the brake elements 62 and 63.

Operation To thread a strip of metal through the device of this invention the mechanism is stopped before the reciprocal carrier 40 makes its back stroke and while the jaw 5-1 is in nonclamping condition, the brake element 62 is lifted by means of the handle 64, the end of the strip of metal is passed between the guide rollers 66, between the jaws 5t) and 51, betweenthe brake elements 62 and 63, and over the die block 5'. The handle 64 is then turned to reset the brake.

While the crank shaft 2 of the power press '1 turns through a half revolution to force the slide 3 of the press downwardly the strip is held stationary and the reciprocatory carrier completes its back stroke, whereupon the brake is released and the clamping jaws 5t} and 51 grip the strip and advance it one step as the reciprocatory carrier 40 makes its forward stroke and the slide 3 ascends. Thus the strip is advanced one step for each revolution of the crank shaft of the press.

The device of this invention is capable of feeding accurately measured increments without slippage at some two and one-half times the rate of which prior art machines are capable.

It is to be noted that the clamping jaws 50 and 51 are made" to firmly grip the strip when the strip and the reciprocable carrier 40 which carries the clamping jaws both are stationary at one end of the stroke; that the strip is gradually started and accelerated and then gradually decelerated and stopped and then held stationary Thus alternate engagement and disengagementof the clamping jaws with the strip occurs while both the strip and the reciprocable carrier are stationary and there is no sudden jerking of the strip.

It is to be understood that the device described in the foregoing specification and illustrated in the accompanying drawings is exemplary only and that it is subject to anticipation and change within the spirit and scope of the disclosed invention.

I claim: 7 1 1.- In a device for feeding strip metal to metal workin apparatus, in combination, a reciprocable carrier, a pair of clamping jaws carried by said carrier, said jaws being adapted to grip a strip'of metal to be fed by said device,

means for sequentially and smoothly accelerating move ment of said carrier on a forward stroke from zero speed to maximum speed, decelerating such movement from 'maximum speed to zero speed at the end of such fonward :stroke, accelerating movement thereof on a back stroke from zero speed to maximum speed and decelerating jaws when said carrier is at zero speed at the end of its forward stroke, the means for causing said clamping jaws to release such strip of metal including a push member having one end acting upon a clamping jaw and a swinging connecting link having a curved surface engageable with the other end of said push member during a portion of the swing of said connecting link, a brake adapted to hold such strip stationary during the back stroke of said carrier, means to apply said brake when said carrier is at zero speed at the end of its forward stroke and means for releasing said brake when said carrier is at zero speed at the end of its back stroke, the'means for releasing said brake including a cam and a slidable member acted upon by said cam, said slidable member in turn acting upon said brake.

2. In a device for feeding strip metal to metal working apparatus, in combination; a reciprocable carrier; clamping means carried by said carrier; said clamping means being adapted to grip a strip of metal to be fed by said device; means for sequentially and smoothly accelerating movement of said carrier on a forward stroke from zero speed to a maximum speed and decelerating 6 its forward stroke including a push member'having one end adapted to act upon said clamping means to release said clamping means and a swinging connecting link having a curved surface engageable with the other end of said push member during a portion of the swing of said connecting link causing said push member to act upon said clamping means.

such movement from maximum speed to zero speed at the end of such forward stroke, and accelerating movement thereof on a back stroke from zero speed to maximum speed and decelerating such movement from maximum speed to zero speed at the end of such back stroke; means for causing said clamping means to grip such strip of metal when said carrier is at zero speed at the end of its back stroke; and means to release such strip from the grip of said clamping means when said carrier is at zero speed at the end of itsforward stroke including a push member having one end adapted to act upon said clamping means to release said clamping means and a swinging connecting link having a curved surface engageable with the other end of said push memberduring a portion of the swing of said connecting link causing said push member to act upon said clamping means.

3. In a device for feeding strip metal to metal working apparatus, in combination; a revoluble shaft; gearing for connecting said shaft tomechanism of a metal working device; a crank fixed to said revoluble shaft, a connecting link pivotally connected to said crank; a recip-;

rocable carrier pivotally connected to said link to be reciprocated thereby; clamping means carried by said carrier; said clamping means being adapted to grip a strip of metal to be fed by said device; means for sequentially and smoothly accelerating movement of said carrier on a forward stroke from zero speed to a maximum speed and decelerating such movement from maximum speed to zero speed at the end of such forward stroke, and accelerating movement thereof on a back stroke from zero speed to maximum speed and decelerating such movement frommaximum speed to zero speed at the end of such back stroke; means for causing said clamping means to grip such strip of metal when said carrier is at zero speed at the end of its back stroke; and means to release such strip from the grip of said clamping means when said carrier is at zero speed at the end of 4. In a devicevfor feeding strip metal to metal working apparatus, in combination; a revoluble shaft; gearing for connecting said shaft to mechanism of a metal working device; a crank fixed to said revoluble shaft, a connecting link pivotally connected to said crank; a reciprocable carrier pivotally connected to said link to be reciprocated thereby; clamping means carried by said carrier; said clamping means being adapted to grip a strip of metal to be fed by said device; means for sequentially and smoothly accelerating movement of said carrier on a forward stroke from zero speed to a maximum speed and decelerating such movement from maximum speed to zero speed at the end of such forward stroke, and accelerating movement thereof on a back stroke from zero speed to maximum speed and decelerating such movement from maximum speed to'zero speed at the end of such back stroke; means for causing said clamping means to grip such strip of metal when said carrier is at Zero speed at the end of its back stroke;

and means to release such strip from the gripof said reverse direction and means to release said brake during the forward stroke of said carrier.

5. The combination defined in claim 3 in which said gearing for connecting said shaft to mechanism of a metalworking device so coordinates the movement of the means for causing said clamping means to grip said strip and means for release such strip from the grip of said clamping means that the mechanism of said metal working apparatus works said strip while said strip is released from the grip of said clamping means.

6. The combination defined in claim 4 in which said gearing for connecting said shaft to mechanism of a metal working device so coordinates the action of said brake adapted to hold said strip stationary during the stroke of said carrier in one direction with the action of said mechanism of said metal working apparatus that said strip is held stationary while said mechanism of'said metal working device works said strip.

References Cited in the file of this patent UNITED STATES PATENTS 1,897,970 Hofmann et al. Feb. 14, 1933 2,582,656 Scher Jan. 15, 1952 2,621,041 Dickerman Dec. 9, 1952 2,670,953 Marsilius -Mar. 2, 1954 2,696,380 Adams Dec. 7, 1954 

